Spectroscopic measurements of electric and magnetic field distributions in a relativistic self-magnetic-pinch diode

The collective motion of charged particles in the gaps of high-current diodes are rather complex, and have been the subject of numerous computations. The only direct approach known for experimental investigation is the measurements of electric (E) and magnetic (B) fields. The spatial distribution of B yields the current-flow distribution, the integral and the derivative of E give, respectively, the potential and the charge distributions. The measurements here were performed on the self-magnetic-field diode [1], powered by the RITS-6 accelerator at Sandia. Visible emission due to plasma formed over the anode surface was used to obtain the Stark shift and Zeeman splitting, giving the axial distribution of E and B at various radii. The axial B distribution demonstrated quantitatively the shielding of B by the anode plasma, and the axial E distribution revealed significant reduction in the effective anode-cathode gap.

Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

[1] K D Kahn et al., IEEE Trans. Plasma Sci. 38, 2652 (2010)